There is much attention currently focused on trying to achieve three energy related and somewhat conflicting energy related objectives: 1) provide affordable energy for economic development; 2) achieve energy security; and 3) avoid the destructive climate change caused by global warming. Many different approaches are being considered to address climate change, including increasing the use of clean, non polluting renewable energy sources such as biofuels, solar, wind and nuclear, attempting to capture and sequester the carbon dioxide emissions from fossil fuel plants, as well as increased conservation efforts. Some of these approaches, such as solar power, have had their large scale implementation blocked due to their current high costs as compared to the cost of fossil based electricity, and other approaches, such as nuclear, are restrained by their environmental and security risks. In fact, the infrastructure and supply for renewable energy is so underdeveloped (e.g., only about 0.01% of our energy is provided by solar) that there is no feasible way to avoid using fossil fuels during the rest of this century if we are to have the energy needed for economic prosperity and avoid energy shortfalls that could lead to conflict.
The climate change threat caused by global warming and the more general recognition of our need to use renewable resources that do not harm our planet has grown steadily since the first Earth Day in 1972. It is mostly undisputed that an increase in the amount of so-called greenhouse gases like carbon dioxide (methane and water vapor are the other major greenhouse gases) will increase the temperature of the planet. These greenhouse gases help reduce the amount of heat that escapes from our planet into the atmosphere. The higher the concentrations of greenhouse gases in the atmosphere the warmer the planet will be. There are complicated feedbacks that cause the amount of carbon dioxide and other greenhouse gases to change naturally even in the absence of human impact. Climate change throughout geological history has caused many extinctions. The concern about the threat of human induced climate change (i.e., global warming) resulted in the Kyoto Protocol that has been approved by over 165 countries and is an international agreement that commits the developed countries to reduce their carbon emissions.
One reason global warming is thought by the Intergovernmental Panel on Climate Change (IPCC) to be a threat is because of the sea level rise resulting from the melting of glaciers and the expansion of the ocean as our planet becomes hotter. Hundreds of millions of people who live just above sea level on islands or on the coasts are threatened by destructive flooding requiring relocation or the building of sea walls if the sea level rises even a meter. There is also a threat to other species from climate change which will destroy ecosystems that cannot adjust to the fast rate of human caused climate change. Additional threats include increased infectious diseases and more extreme weather as well as direct threats from extreme heat.
We can demonstrate the challenge of dealing with global warming using a simple model. Let CCA(YN) represent the carbon dioxide added to the atmosphere in year YN in gigatonnes per year. Similarly, let CEX(YN) equal the amount extracted, CEM (YN) the amount emitted by humans and CN(YN) be the amount either added or removed due to natural variations in the carbon cycle. Today, the land stores each year approximately 1.8 gigatonnes (109 tonnes) of carbon dioxide and the ocean approximately 10.5 gigatonnes (note carbon dioxide is 3.66 times heavier than carbon), while the amount humans add by emissions is about 24 gigatonnes of carbon dioxide. More generally, we have:CCA(YN)=−CEX(YN)+CEM(YN)+CN(YN)  (1)CA(YN+1)=CA(YN)+CCA(YN)  (2)where CA(YN) is the amount of carbon in the atmosphere in year YN, 2780 gigatonnes of carbon dioxide today. Other forms of carbon contribute to global warming, most notably methane, although by weight they represent a small component
If CEX(YN) is set to zero than the only way one could possibly stop adding carbon dioxide to the atmosphere would be to reduce our emissions to be equal to the natural uptake. However, CN(YN) itself varies greatly and can be a net addition to the atmosphere from the much larger natural carbon cycle which adds and subtracts carbon at about 750 gigatonnes of carbon per year. It is the shifts in this natural balance that has caused climate change before our species existed and will also continue to do so in the future. Thus, it is clear that there is no solution that only reduces human contributions to carbon dioxide emissions that can remove the risk of climate change. With air extraction and the capability to increase or decrease the amount of carbon dioxide in the atmosphere one can in principle compensate for other greenhouse gases like methane that can change their concentrations and cause climate change.
Accordingly, there is a broadly recognized need for a system and method for reducing the amount of carbon dioxide in the atmosphere created by burning of fossil fuels and for providing a low cost, non-polluting renewable energy source as a substitute for fossil fuels.